The present invention pertains generally to a device capable of distributing, routing and managing a plurality of conductors such as optical fibers and metal wires, and more particular, to a mechanical device that does not rely on the use of adhesives to distribute and manage the conductors. The inventive device finds use in integrated printed circuit boards assemblies, among other applications.
Today, many applications contain printed circuit boards (PCB) that integrate optical and electrical components to increase the data transmission and storage capabilities. Such applications include, e.g., computers and telecommunications (in door and outdoor). On the optical side, typically several optical fibers from four to thirty-two or more, are used raising fiber management issues. To complicate the matter, the numerous optical fibers usually also need to be distributed and routed to a specific location on the PCB. Some skilled in the art have tried to address these issues.
For example, U.S. Pat. No. 5,204,925 (Bonnani et al.) discloses an optical interconnection apparatus having a flexible substrate and a plurality of optical fibers mounted on the substrates. The substrate has a main body portion and a plurality of tab portions extending from the body portion. The optical fibers are mounted to the substrate so that each fiber has its end extending between two of the tabs. In this fashion, a fiber distribution network is formed on the substrate. The fibers are mounted by depositing a pressure sensitive adhesive on the flexible substrate and/or on the fiber jacket and then laying down the fiber in a desired pattern. In one embodiment, after the fibers are mounted to the substrate, a cover layer is formed over the fibers and the substrate. In another embodiment, the tab portions are capable of twisting at an angle with respect to the main body. A method of making an optical interconnect apparatus is also disclosed.
As another example, FLEX-FOIL(trademark), a currently commercially available product, contains, in general, optical fibers or copper wires adhesively bonded to a flexible substrate. If desired a cover layer can be disposed on the fibers and the substrate.
The art described above rely on one common featurexe2x80x94the use of an adhesive to bond the optical fibers or copper wires to the substrate. While the adhesive method may be useful, it has some accompanying drawbacks, such as, e.g., nearly permanent placement of the fibers, added processing steps for adhesive bonding, and possible outgassing of volatile organic components in the adhesive due to temperature and humidity effects.
Thus, there is a need for other devices or apparatuses that can manage, distribute, and route conductors, such as optical fibers and copper wires, without the use of an adhesive.
The present invention provides for a new mechanical device that is capable of managing, distributing, and routing conductors without resorting to the use of an adhesive. The inventive device can be manufactured economically in a streamlined manufacturing process. In general, the inventive device can be constructed by patterning features into a flexible substrate. For example, illustrative features include those that can hold interconnect components, those that allow for folding of the device, those that define the circuit (optical or electrical) routing paths, those that allow for a reservoir of the conductors, and those that allow for safe minimum bend radius of the optical fibers when they are used.
The device can be spatially defined using the Cartesian coordinate system, i.e., a three-dimensional coordinate system in which the coordinates of a point in space are its distances from each of three perpendicular lines (x, y, and z) that intersect at an origin. The x coordinate represents, e.g., the general width of the device while the y coordinate represents the length and the z coordinate represents the thickness. The device is predominantly defined by the plane created by the x and y coordinates because it has minimal thickness.
As used herein, the term xe2x80x9cflexible,xe2x80x9d when used to describe the substrate, means generally that the substrate has the capability of being bent repeatedly without substantial damage to it. In a preferred embodiment, the device has out-of-plane flexibility, that is, out of the x-y plane. The device does have flexibility in-plane.
In one preferred embodiment, the interconnect device comprises conductors and a flexible substrate, the flexible substrate having (a) a central body having at least one input end where the conductors enter; (b) a plurality of primary tabs extending from the central body, each tab having at least one means for retaining the conductors; and (c) a passageway formed from folding the device along a plurality of folding slots such that a plurality of locking features mate with a plurality of interlocking slots and the primary tabs. The conductors disposed inside at least a portion of the passageway. The device manages, routes, and distributes optical fibers without the use of an adhesive.
In another preferred embodiment, the inventive device is for optical fibers and comprises a flexible substrate having (a) a central body having an input end; (b) a plurality of tabs extending from a portion of the central body, each tab having at least one means for retaining the optical fibers; (c) a plurality of locking features extending from a second portion of the central body; and (d) a plurality of folding features disposed on the central body. The device is capable of managing, routing, and distributing the optical fibers without the use of an adhesive. In yet another embodiment, the device further comprises a retermination loop.
As stated, one advantage of the present invention is that it does not rely on an adhesive to bond the conductors to a substrate like FLEX-FOIL(trademark) or like U.S. Pat. No. 5,204,925. Instead, the invention relies mainly on features patterned into the substrate that can manage and route the conductors. In this way, the conductors are managed, distributed, and held in place mechanically without bonding them permanently to the substrate. Thus if desired, such as during in a repair or rework step, the conductors can be moved.
Another advantage of the present invention is that the device can be manufactured easily and cost effectively. In brief summary, a roll of flexible substrate is supplied. The device will have a certain desired configuration or design. This configuration can be generated using computer-aided design (CAD). The CAD configuration is inputted into a computer controlled manufacturing machine that converts or patterns the roll of flexible substrate to the desired configuration. In one preferred method, a laser, such as a CO2 laser, patterns the substrate by cutting the desired configuration. One skilled in the art will recognize that the type of laser used to pattern the substrate will depend on the type of substrate chosen.
Yet another advantage of the invention lies in its versatility and ease of use. The device is versatile in that it can be readily patterned and manufactured to accommodate any desired configuration as described above. Because of its flexibility, it can be easily elevated away from the PCB to allow for air-flow over the chips thereby cooling them, if needed. The device can also be designed with a specific layout to avoid particular areas, for example areas on a PCB that may require cooling. It is easy to use in that the optical fibers and connectors can be pre-assembled independent of the PCB and when needed, the assembled device simply plugs into the PCB or its intended destination of use. Finally, the device can be readily reworked if needed.